Leaving DNA on the shelf is a crime

The prosecutors say that even if the tests come back negative for Savory, they wouldn't matter because there was other evidence against him. Wouldn't matter? Imagine, if you can, a prosecutor who wouldn't introduce DNA evidence supporting his theory -- no matter how good his other evidence might be. In any case where a criminal has left biological traces at the crime scene, DNA matters a whole lot. It trumps just about everything.

It may be that DNA analysis would come out in Savory's favor. But it's also possible it will confirm the verdict against him. Convicted rapist Rubin Weeks went to the Missouri Supreme Court seeking DNA testing, and the court granted his wish. When the DNA results came back, they said: Yep, you've got the right guy. In about half of all such cases, that's what happens.

Most prosecutors are upright public servants who have no desire to punish people who don't deserve it. In recent years, the great majority has come to accept the value of post-conviction testing in cases where it might yield valuable information.

In Cook County, Ill., the state's attorney has set up a DNA review unit to find such cases on its own (though it has gotten mixed reviews). No fewer than 41 states have passed laws to let inmates petition for testing.

But some government lawyers still take any request as an invitation to run screaming from the room. Two men who had served almost 20 years were recently exonerated by DNA only after a court mandated the tests over the objections of Baltimore prosecutors. A federal judge in Alaska recently ruled against prosecutors and ordered the state to allow DNA testing in a 1993 rape case, at the request of a convicted man who says he is innocent.

Like football coaches, stock analysts and newspaper columnists, prosecutors are human and sometimes screw up. They should welcome a tool that helps uncover devastating errors. When a prosecution has gone wrong, it's never a mistake to get it right.